Donnerstag, 22. April 2010

Natural events or presumed catastrophes will always lure from their hideouts religious fanatics and other self declared experts.

The ongoing eruption on Island for example was interpreted as a side effect of the HAARP-Project, related to sun activity and first signs of the end of the world (coming in 2012).No wonder that even the official religon(s) now have to contribute their explanation - the Italian theologian Antonio Rungi (I presume he is catholic) sees it as divine act: "The volcanic cloud that blocked air transport in Europe is - if we interpret it in the light of the Gospel and the Apocalypse - certainly a proof of God. Just a volcanic eruption to undermine the whole system, this makes us realize how precarious we are".

But this is not even the dumbest opinion on the eruption:The NATO was also portrayed as guilty, because the military exercise "Brilliant Mariner " should to be hold just during the ongoing eruption and consequent closure of commercial air routes, and naturally from these “facts” some connections to 9-11 are postulated.Funnier is the alleged connection of the Icelandic volcano to a possible extraterrestrial invasion, Agent Spooky-Mulder would be pleased.

Meanwhile the German bio-physician Dieter Broers is cited in the German tabloid BILD: “NASA images show just one day before the eruption the largest solar flare in 15 years. - He is certain: The earth is heading to a doomsday triggered by the Sun in 2012.”

The tabloid, notorious known for its approach to science, continues with a list of other “incredible“explanations:

The German author Hartwig Hausdorf, dedicated “mystery researcher”, postulates a connection between the American HAARP-project and the volcano, a other author, Walter-Jörg Langbein clearly sees a ethical motivation behind the behavior of the volcano – our civilization, like the Maya, is to arrogant and must be punished.

Hydrobiologist and journalist Edgar L. Gärtner got the simplest of all explanations “There is no ash-cloud”. The entire story is only a conspiracy and a deflection strategy to prepare a terror attack of incredible proportions.What else? Maybe that the ash is a strategy of the living planet, named after the Lovelock hypothesis Gaia – to reduce the of CO2 influx by airplanes? Or got the old Vikings it right, and is Eyjafjallajökull only the beginning of Ragnarök, and will be Iceland the battle ground of Thor and the Midgard serpent ?

Don´t even bother to ask a geologist... It’s seems that a geological explanation like Iceland is sitting on top of a magmatic hot spot is too unrealistic. Let’s remind of the good times, and the religeous mumbo-jumbo when volcanoes where simply calmed by a human sacrifice - so let’s use some geologist, it’s seems that anyway nobody is listening to them.

Dienstag, 20. April 2010

Callan Bentley at Mountain Beltway will be hosting the next edition of The Accretionary Wedge and he is searching heroic earth scientists.

I was influenced by many people in my approach to geology, contemporary parents, friends and teachers, but also by historic personalities in form of their biographies and achievements in science.Nevertheless I wouldn't speak about them only as heroes - they were after all men, and displaying them as infallible scientist seems somehow to put them on an unattainable podium.Let's also remember the words of the theoretical physicist Philippe Blanchard

"The scientist should take the science seriously, but they should not take themselves to seriously."

People that propose revolutionary ideas, ahead of their time, often get misunderstand, even attacked verbally and ridiculed. William Smith for example, considered a pioneer of stratigraphy, was nicknamed "Strata-Smith" after his proposal that the earth is organized in defined layers. And the caricatures of Charles Darwin and Thomas Henry Huxley are today part of history.On the other hand, some personalities gather such a reputation, that no critic is allowed or tolerated. Criticism can only be addressed in a indirect way, for examples by caricatures or satiric drawings.Even if it's exactly not the gentlemen's way (or perhaps it is - the best known examples are made by Victorian gentlemen in the golden age of geology in the years between 1780 and 1900) satirical drawings, in a certain manner, are a funny way to criticise - both in a fair or unfair manner.A caricature can refer to a portrait or a behaviour that is exaggerated or distorted, the sense of a satirical drawing is to capture the essence of a person or thing to create an easily identifiable visual likeness - the drawing should be simple, but unmistakable for someone that has some background information (for example knows the depicted person or the context) and transport as much meaning as possible. Although this kind of satire is usually meant to be funny, its deeper purpose is often an attack on something strongly disapproved by the satirist, using the weapon of wit.But these prerequisites make the drawings also a source of information's to explore the history of earth sciences, the caricatures carry a lot of information, not only about the depicted person or geological model, but also how new theories are accepted or refused by society, and as last but not least, the personal opinion of the caricaturist on the matter.

The first geologists had to face many prejudices and hostilities, like James Hutton (1726-1797), facing the many critics of his ideas on deep time and rock formations.One of the most famous caricatures, depicted many times in books dealing with geology and palaeontology, was produced by the English geologist Henry De la Beche (1796-1855) to lampoon the theories of Charles Lyell.

Fig.2. "Awful Changes.", see also the Ichthyosaurus installment at ART evolved.

The prominent "Professor Ichthyosaurus" was considered first to represent William Buckland (1784-1856), but the geologist and dedicated earth-science historian Martin J.S. Rudwick realized the connection of this scene with some drawings produced in 1831 by De la Beche in his diary, where he ridiculed the uniformity-principle of Lyell.Lyell proposed that even if earth is much older then previously thought, and the forces that sculpt the planet are inexorably but slow, these forces follow a eternal circle of climate and fauna - so in a distant future, after our recent ice age, it is may possible that after mammals again reptiles live in a greenhouse (note the palms in the background), following as highest "social class" the human race.

In the other drawings of De la Beche diary a lawyer (the reference to Lyell seems obvious) is carrying a bag with "his" theory around the world, or he is shown wearing particular glasses to see the world in a personal view, and offering this "theoretical approach" to a geologist carrying a hammer, a reference to the applied working researcher. It's obvious that De la Beche could not overcome his prejudice against Lyell as a lawyer, that he considered much more a theory foreigner then a real researcher (considering how much Lyell travelled and how much geological phenomena he visited this is a very unfair insinuation).In a second cartoon (brought to light by Haile 1997) De la Beche is mocking on the effects of present causes, operating at the same slow magnitude and rate throughout geologic history. We see a vast U-shaped valley, and in the foreground a nurse with a child.

Fig.3. De la Beche´s cartoon of 1830-1833 mocking the effects of present causes. The cartoon is entitled "Cause and Effect".

The child is peeing into the huge valley and a caption has his nurse exclaiming, 'Bless the baby! What a valley he have made.!!!'

On the 24 July of 1837 the Swiss geologist Agassiz was to be thought to hold a lecture about his studies on fossil fishes - instead the members of the venerable Swiss Society of Natural Sciences heard from their young president a theory, emerged some years before, to explain the origin of erratic blocks and scratches on rocks in the Alps. "O Sancte de Saussure, ora pro nobis!" - O holy de Saussure, pray for us, was the only comment of the German geologists Leopold von Buch (1774-1853) as he left the room. Another proposed great idea caused disbelief in the public and gave cartoonist much to work on. Agassiz showed in his study "Études sur les glaciers" (1840) that glaciers were the explanations of erratic blocks and scratches on rocks in the Alps, the idea of a large ice cap covering the Alps, and the Ice Age was ready to meet the broader public.

Agassiz introduced with his former mentor Buckland in the autumn of 1840 the glacial theory to the British Isles.Professor Buckland, was a highly respected scientist, but also eccentric and very perky, and in a first moment struggled with the idea of his friend Agassiz, but became convinced after he saw the spurs of glaciers and moraine deposits in the Alps and Scotland.Maybe the public was anyway chuckling over the debate about the importance that highly respected men gave to this apparently tiny marks on rocks, in every case the well-known mining engineer Thomas Sopwith (1803-1879) thankfully poked fun on his fellow countryman and on the subject of the dispute.

Fig.4. Costumes of the Glacier.

The cartoon sketch that he scratched/draw of the Professor, titled "Costumes of the Glaciers", shows Buckland dressed for fieldwork. The numerous captions are difficult to read, but the lines at Buckland's feet are noted to be "Prodigious Glacial Scratches" produced by "the motions of an IMMENSE BODY, not allow to change its course upon Slight Resistance" (we ignore if this is referred to the glacier or the appearance of Buckland). Buckland holds - like all true geologist do - a geological map under his arm, a "Map of Ancient Glaciers".On the erratic stones scattered around his feet's captions tell, that this stone was scratched 33.333 years ago, but on a other rock this prodigious age is relativated, claiming that a similar looking stone was just scratched by the wheel of a passing cart, just the day before yesterday, and in the background it's seems that some new scratches are just in the making by a passing carriage.

Caricatures and cartoons can bring science and scientific discussion to the attention of a broader public, but to appreciate them, they have to be understood.What I choose, are only two examples and theories, and many others were worth to be told, but they show us how certain geologists and their support of new ideas have influenced society, and how they were seen by their contemporaries, and how society understand (sometimes wrongly) the work of the researchers.

We are only humans - and maybe that’ s the most important teaching that cartoons can give to us.

Freitag, 16. April 2010

The ongoing eruption of the Icelandic volcano Eyjafjallajokull caused much interest in the geoblogosphere (Italy, Portugal, U.S.A and Outside,geologists - but also paleontologists get interested, and of course magmaliceous volcanologists here and here) mainly because of the spectacular pictures available, but it's a reminder also for an interesting phenomenon, related with Quaternary geology. (so we got also Quaternologists).

Large volcanic eruptions throw huge amounts of ash and aerosols in the upper parts of the atmosphere, here atmospheric currents take the particles and distribute them widely, in some cases even around the planet. Sometimes this ash, or better it's effect, is seen in the sky, the dust particles and sulfur droplets deflect the sunlight during sun rising and setting, and turn the sky in vivid red colours. The fine particles will float in the atmosphere for months or even years, and finally sink to the bottom of the air ocean and deposit on the landscape.

Fig.1. Tephra layer of the Laacher See volcanic eruption dated to 12.900+-560yr BP (with dendrological cross-references 12.916yr BP) in the limnic marls of the French lake Lautrey.

-they are erupted over very short time periods, geologically speaking, usually a matter of only hours or days to perhaps weeks or months

-they can be spread widely over land and sea to form a thin blanket that (unless reworked) has the same age wherever it occurs.

- The volcanic minerals can be dated by radiometric methods (Argon40-Argon39 for example)

- For some events we possess written reports, so if the layer is attributed to a determinate eruption, we can very precisely date the sediment. Historical accounts have provided accurate eruption years for many eruptions in countries where volcanic activity is common, in particular during the last 200-300 yr. In Europe historic events are recorded for 1783, when the ashes originated from the Icelandic Laki volcano reached the continent, Tambora in 1815 (recognized as volcanic event in Europe only with ongoing scientific research in 1855), Krakatau in 1883.

Therefore, once it is identified by its mineralogical and geochemical properties, a tephra layer provides a time-parallel marker bed or isochron for an 'instant' in time, and with this marker horizons a Tephrochronology of sediments can be established. Tephrostratigraphy' is another term that is commonly used and refers to the study of sequences of tephra layers and related deposits and their relative ages. Sigurdur Thorarinsson, an Icelandic volcanologist (who else?) is widely regarded as the modern 'father of this discipline, he realized in the twenties of the past century that the numerous Icelandic tephra layers offered great possibilities for correlation and dating.After the first pioneering work, studies of tephra layers spread in the 1920s and 1930s in New Zealand, Japan, Iceland, South America and USA.

In Europe important sources for quaternary volcanic ashes are the larger volcanic districts, like Iceland, the Italian volcanoes (comprising active volcanoes as the Pleistocene volcanoes of Monticchio), the Auvergne in France, the Eifel in Germany with the important marker horizon of the Laacher See Tephra, the (ex-)Thera volcano in the Mediterranean Sea.

Fig.2. Known distribution of major tephra localities and related volcanic districts. Iceland - Vedde Ash (VA), Germany - Laacher See (LST), and Italy - Neopolitan Yellow Tuff (NYT). The locations of the principal volcanic centers that were active during the period ca. 18.5 to 8 14C kyr BP are also identified (from ALLOWAY et al. 2007). It´s interesting to note that the fossil Vedde Ash distribution is similar to the recent ash-plumes over Europe (and here).

Donnerstag, 15. April 2010

Since a French geology student visited the remote region nearly 50 years ago, and brought back tales of fossil rich sediments, the area around the river Awash is considered a "must seen" for paleoanthropologists and geologist interested in the natural history of Africa.

Fig.1. Mentioned hominid bearing sites, Aramis near the river Awash in Ethiopia and Malapa in South Africa.

The presentation to the public of Ardipithecus ramidus, found at the site of Aramis in the catchment area of the river Awash, in October 2009 was a media event comparable to the presentation last week of Australopithecus sediba from South Africa.But both described species are only a part of the recuperated evidence (in case of A. ramidus nearly 150.000 bone fragments), behind A. ramidus there lie 15 years of research, behind A. sediba 2 years - the paleontological and geological results of both sites shamefully received little attention in the mass media.But the careful collection and examination of animal and plant fragments, and the geological framework, was rarely well documented as by these two discoveries.

The proposal of Darwin that Africa is the cradle of humankind led to the idea that the last common ancestor, which we share with the great apes, lived like the recent chimpanzees or gorillas in a forest habitat.Then, in 1925, the discovery of the first Australopithecus species, considered a early hominid, by Raymond Dart seemed to give further clues of human evolution.The associated faunal remains showed that Australopithecus lived in a grassland environment, it was therefore speculated that the open grasslands of Africa - developing in the Pliocene ice ages - were exploited by early hominids and were therefore somehow integrally involved with the origins of upright walking, a possible key factor of our further evolution.

But the sediments and the paleontological content of the Lower Aramis Member (Sagantole Formation) at Aramis provided evidence that Ar. ramidus lived in a predominantly woodland setting - upright walking of early hominids was therefore primarily not an adaption to overlook or to colonize a grassy savanna.

Taphonomic assemblages often represent a collection of a variety of animals of different geographically locations and time periods. Carcasses of animals from different environments can be washed together, or natural traps, like caves, act as sample bag for many centuries, providing a false species assemblage. Accurate interpretation of fossil assemblages can be challenging.In the case of Aramis however, the sampled stratigraphic unit is sandwiched between two volcanic horizons, which yielded approximately the same age (4.4Ma), supporting the idea that the fossils represent a short time intervall.The fossils of Aramis comprise a large variety of plants and animals, including insects, molluscs and bones of owls, parrots, porcupine, hyenas, bears, elephants, ancient horses, giraffes, antelopes and rhino.The recovered bones of birds and mammals came from species living in, or associated with, closed forest or shrublands.One of the common larger mammals found associated with Ardipithecus is the spiral-horned antelope, or kudu (Tragelaphus).

Fig.2. A not so scientific reconstruction of a possible hominid habitat.

Today, these antelopes are browsers eating mostly Leaves, and they prefer bushy to wooded habitats. In contrast, remains of grazing antelopes are rare in the Aramis assemblage.The environment of these animals can also be reconstructed by analyzing their teeth's. Carbon isotopes from tooth enamel yield dietary information because different isotope signatures reflect different photosynthetic pathways of plants consumed during enamel development. Therefore, animals that feed on tropical open-environment grasses (or on grass-eating animals) have different isotopic compositions from those feeding on browse, seeds, or fruit from shrubs or trees. The isotopic pattern of Ardipithecus is also similar to that of Tragelaphus, indicating little dietary intake of grass, and supporting the reconstruction that the animal lived predominately in the forest.

Additionally, oxygen isotopes, found also in the molecular structure of the enamel, can be used to reconstruct the relative humidity and evaporation (temperature) in the environment where the animal, and with it the teeth grow.

The death of an animal is the last act in life, and the first step to go lost forever, or in rare cases become buried deep within earth, get fossilized and in even more rare cases being excavated by naked monkeys. But how to reconstruct these events, where no living eyewitnesses are allowed?

Let's see what the rocks can tell us.The two skeletons of Australopithecus sediba were discovered in cave infillings of the karst landscape of South Africa, in a massive, up to 1.5-m-thick stratigraphic unit containing abundant, well-preserved macro- and micromammal fossils, including articulated remains of Equus sp.The poorly sorted, coarse-grained and cemented sandstone consists of grains with diameters ranging from 0.5 to 2.5 mm of quartz, chert, dolomite, peloids and, less commonly, iron oxide-coated grains, ooids, shale, and feldspar.Angular limestone blocks (smaller than 50 cm) and flowstone fragments (smaller than5 cm) occur throughout this facies. The heterogenic lithological composition tells us that the sediment - or parts of it- is allochtonous, the material of this facies was transported, maybe from outside, and deposited in the cave.

Fig.4. Geological map of the Malapa site, after DIRKS et al. 2010.The fossils of hominids where interbedded in facies D. The underlying flowstone was also dated by U-Pb on an age of ca. 2 Ma.

The heterogeny in the grains, ranging from sand to pebbles to larger boulders and fossils, and lacking sedimentary structures (like stratification) suggest the deposition of the unit as a single event, like a debris flow, maybe caused by a flood or a storm. The superb preservation and state of articulation of fossil material also indicate rapid deposition, limited transport distance, and laminar flow conditions consistent with debris flows.

These new data and the combination of different scientific approaches questions old certainties. The case of Ardipithecus suggests that the anatomy and behaviour of early hominids did not evolve in response to open savanna or mosaic settings.In the case of A. sediba the geology tell us how hominids become fossilised and where we must search for them. The fossils found with A. sediba helped also to date the new species, and confirmed the radiometric ages, a faunal analysis is still missing, but who knows if further investigations will not force us again to change our understanding how we evolved.

Dienstag, 13. April 2010

A part of a glacier broke off and plunged into a lake in Peru, causing a 23m tsunami wave that swept away at least three people and destroyed a water processing plant serving 60,000 local residents, government officials said Monday. From msnbc

Montag, 12. April 2010

Bozen, 12 April 2010: 9 confirmed victims, 23 people injured, these are the latest sad information’s about a rail crash between the towns of Latsch and Kastelbell in the South Tyrolean “Etschtal”, occurred at 9.00 p.m. this morning. The railway between the two localities follows the orographic right bank of the main river of the valley “Etsch/Adige” in a gorge eroded by the river in Holocene sediments (manly a large alluvial fan coming from south with unconsolidated debris-flow deposits).

A landslide of 400 cubic meters - with a width of 10 to 15 meters, and a thickness of 2m - bursted off 50m above the railway line and hit the first wagon of the train, that was just passing by in direction of Kastelbell, causing the train derailment.

To clarify possible causes of the landslide, geological investigations are underway. Eye witnesses reported large quantities of water running down the slope after the accident. A site investigation by the authorities preliminary concluded, that it’s possible that the rupture of an irrigation system above the location of the accident (the area is used for agriculture and farming) saturated the soil and underlying sediments with water, causing a mudslide just in the moment the train passed the point. The irrigation system, after the winter, was used since the last week, it’ s seems that at least in the last days to hours water infiltrated in the underlying slope. It’s also possible that the vibrations of the approaching train triggered finally the slide.

Fig.1. Location of the mudslide between the towns of Latsch and Kastelbell, ca. 1,4km after Latsch, from where the train was started some minutes before the accident (yellow circle) - the railway line follows the escarpment of the river “Etsch/Adige” between the two towns. The landslide happened on the orographic right bank of the river, in soil and sediments of a large alluvial fan. Coordinates of image centre: 46°37`43´´N and 10°52´54´´E (Product of the Autonomous Province of Bozen/Bolzano - South Tyrol)

I wish to express my condolence to the families of the victims, and thank the emergency services for their rapid intervention - only minutes after the accident they arrived on the place, and worked until now (11 hours) to rescue injured peoples.

Sonntag, 4. April 2010

"Mom for baby-mammoth" is an old soviet cartoon inspired by the discovery of baby "Dima" in 1977. This little masterpiece tells the story about baby mammoth that miraculously avoided extinction and started the quest for his mom search (found on Siberian Mammoth).

Abo

Just reading

SPÖTL et al.(2006):The last and the Penultimate Interglacial as Recorded by Speleothems From a Climatically Sensitive High-Elevation Cave Site in the Alps. In SIROCKO, F. et al. (ed): The climate of past interglacial. Developments in Quaternary Science 7.